Because futures trading is a standard contract, this can be done, because every contract of the same month has the same quality requirements, quantity and so on, and there is a credit transaction problem. For example, we are not in the futures market, but in the real market. I place an order with you and ask you to deliver 1 month 1000 tons of soybeans. You didn't, but you know a place where you can buy it at a low price. So you promise me that you can deliver the goods first, and then you can buy the spot at a low price and sell it to me. This is short selling, also known as empty gloves and white wolves. Haha, the same futures, you can have nothing at hand, first make sure you can sell it, and then buy an identical contract. Then the computer system will automatically offset what you buy from what you sell, and the difference between them is profit or loss.